Some in defense circles say it is the result of election-year politics and members of Congress will realize next year that they need to heed top Pentagon officials who have testified that they have too much infrastructure and not enough money.

“It is election-year posturing,” said an aerospace executive who monitors BRAC.

Others are not so sure, saying base closings would put thousands of people out of work in a tepid job market.

“I do not think the appetite will go up postelection,” said Steven P. Bucci, a Heritage Foundation military analyst who served as a senior Pentagon official in the George W. Bush administration.

“Congress has never shown any appetite for any BRAC because they, Congress, are by design taken out of the process,” he said.

“A BRAC commission does the research, makes the recommendations for closures, and then everyone has to basically ‘eat’ the results. I sound harsh, but Congress sees the protection of jobs and installations in their districts and states to be their duty,” Mr. Bucci said.

With BRAC, Congress stays mostly on the sidelines. It can lobby the commission, but the commission’s closure list can be accepted or rejected only in full.

Cutting troops, not bases

The Republican-led House already has passed the no-BRAC bill crafted by its Armed Services Committee, and the Democrat-led Senate panel has approved unanimously its defense bill omitting base closures.

A conference committee to reconcile the bills will have no pro-BRAC members, thus delaying the base-closing process for at least a year.

Mr. Panetta has said he needs to close bases and small installations to help him achieve $487 billion in congressionally mandated spending cuts over the next 10 years.

The final defense spending bill not only will deny a new BRAC but also likely will include language that prohibits the military from taking unilateral action to close small facilities without prior White House notification to Congress.

A Pentagon spokeswoman declined to comment when asked what options remain, saying the legislative process is not complete.

To meet budget-cutting demands, Mr. Panetta is slashing Marine Corps and Army troops by 90,000, while the Navy and Air Force are trimming manpower on a smaller scale.

The Air Force has provided a snapshot of how to reduce operating costs without necessarily shuttering buildings. It announced in March a series of unit deactivations, such as a 600-troop communications unit known as the Third Herd at Tinker Air Force Base in Oklahoma.

The Air Force is targeting big and small, even reaching down to deactivate bands, such as the Band of Liberty at Hanscom Air Force Base in Massachusetts.

The overall plan is to reduce manpower by 3,900 active airmen, 5,100 Air National Guardsmen and 900 reservists.

Some defense sources say the Air Force has an excess of training centers and bases for bombers and cargo planes.

Military investments

Retired Gen. T. Michael Moseley, former Air Force chief of staff, said it would be a mistake to close centers where pilots learn to fly supersonic jet fighters and long-range bombers.

“One thing that is a given for the United States Air Force is: Always train pilots. Always,” said Gen. Moseley, a former fighter pilot. “Never ever, ever miss a chance to keep the numbers robust and the training baseline robust. You can always take a pilot and use them somewhere else. You cannot go the other way.”

He drew a distinction between the investment in a pilot and in a soldier.

“By the time you get this guy or gal into a squadron, you’ve already got between six and seven years tied up in this kid,” he said. “You can create an Army rifleman or a Marine rifleman inside a year. You can’t create a pilot of a high-performance airplane inside that time period I outlined.”

Gen. Moseley, who ran the air campaign in the 2003 invasion of Iraq to oust Saddam Hussein, said that while base closures need to be studied, so do the sizes of the Army and Marine Corps — what is called end strength.

Gen. Moseley, like several other retired fighter jocks, is upset that the Pentagon ended procurement of the F-22 Raptor stealth fighter short of what Air Force commanders said was needed.

“We’re out of Iraq,” he said. “We’re going to come out of Afghanistan. Isn’t it time to look at some of the strategic throw-weights, the things that actually deter and dissuade and persuade? Wouldn’t that be something that looks like Navy and Air Force investment?”

Military real estate

The Pentagon publishes an annual report on the real estate it manages around the world.

Referring to the Pentagon’s “vast portfolio,” the report says it operates 542,000 facilities at 5,000 sites on more than 28 million acres.

In the U.S., the Pentagon operates 4,127 sites, including a reserve training center, an ammunition depot and a sprawling Army base. Each site would be reviewed by the military if Congress were to approve a base closure commission.

After the last BRAC assessment, seven years ago, the commission closed 185 sites and realigned 135.

Heritage’s Mr. Bucci said “it is near impossible” for the Pentagon to close a base unilaterally.

The president has the authority to do so, but lawmakers have set up speed bumps that require the Pentagon to first notify Congress if a site employs a certain number of workers.

Choosing to close one base over another could spark a civil war on Capitol Hill, as well as moves to block closure by crafting legislation to deny needed funds.

Without a BRAC, pending automatic defense spending cuts of more than $500 billion, set to begin in January, become even more damaging, Mr. Bucci said.

“If you cannot close installations, the only way to make those draconian cuts is to eliminate people and modernization programs,” he said. “This too will kill jobs, both in the military and in any associated businesses.”